A good website should provide all of options for its users.
I had suggested to implement web version for mobile also, but team like to encourage play with apps on mobile and web version for PC users. That's the reason website is visible two different mode on mobile and pc. However, if you like to play on mobile web version then turn on "Desktop Mode" from your browser. Then it will show like you are on PC and you might play as well. Otherwise you have to install apps.